Impact du Rouissage en Champ sur la Structure des Fibres de Chanvre.

In the hemp industry, retting is considered as an upstream processing treatment that facilitates the decortication of fibres in the central woody part of the stem. This treatment is currently carried out empirically in the fields, and leads to variability in the color, (micro)structure and intrinsic properties (thermal properties) of hemp fibers. The present study aims to compare unretted and retted hemp fibres harvested at the end of flowering. The results show that retting induces a change in the color of fibres from light green to dark gray due to the activity of the microbial community at the stem surface. A separation of the fibre bundles into elementary fibres occurs with the degradation of the cementing compounds present in the middle lamella. The cellulose and its crystallinity degree increased from 68 to 75 % and 85 to 89 %, respectively, with a removal of non-cellulosic materials, which leads to an improvement of the thermal stability for the retted fibres. [ABSTRACT FROM AUTHOR]